Etude expérimentale du bruit de choc de jets coaxiaux

B. Andre, T. Castelain, C. Bailly, D. Juve

Description

10ème Congrès Français d’AcoustiqueLyon, 12-16 Avril 2010Experimental investigation of screech by an underexpanded supersonicjet with forward flight effect1 1 1 1Benoît André , Thomas Castelain , Christophe Bailly ,DanielJuvé1 Laboratoire de Mécanique des Fluides et d’Acoustique, École Centrale de Lyon,36 avenue Guy de Collongues, 69134 Écully CEDEX, France, Email : [e-mail] coaxial supersonic facility has been upgraded in the anechoic room of the Centre Acoustique (LMFA,Ecole Centrale de Lyon) to reproduce a supersonic fan flow in forward flight. This paper first presents thisnew facility and some validation tests. A and B screech modes are characterized. Near-field microphonescan well discriminate these two modes. A chaotic behaviour is found for mode B, which cannot beexplained by mode switching. The effect of secondary flow on screech is essentially a decrease in frequency.Frequency jumps and hysteresis have also been observed with flight speed.lity and instrumentation are provided in section 2. Sec-1 Introductiontion 3 deals with acoustic results on screech. ConcludingIn modern engines, the exit flow is separated into a remarks are finally given in section 4.hot supersonic core flow and a cold supersonic fan flowby two nozzles for cruise conditions. In the latter, there2 Experimental apparatusoccurs a pressure mismatch at the exit which entailsthe generation of a shock cell structure in the jet. The2.1 The dual-stream wind tunnel ...

Informations

• Publié par: Uste
• Nombre de lectures: 35
• Langue: English

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